6 And that the disciples too were bound up with Paul with all perfectness; and that not men only, but women also, hear what he says about Phœbe. “Now I commend to you Phœbe the sister, being a deaconess of the Church which is in Cenchreæ; that you may receive her in the Lord worthily of the saints, and stand by her, in whatever matter she may require you, since she has proved a helper of many; and of me myself.” But in this instance he bore witness to her of her zeal so far as help went (only:) but Priscilla and Aquilla went as far even as death for Paul's sake; and about them he thus writes, saying, “Aquila and Priscilla salute you, who for my life's sake laid down their own neck;” for death clearly.
And about another again writing to these very persons he says, “Because he went as far as death; having counselled ill for his life, in order that he might supply your deficiency in your service towards me.” Do you see how they loved their teacher? How they regarded his rest before their own life? On this account no one surpassed them then. Now this I say, not that we may hear only, but that we may also imitate; and not to the ruled only, but also to those who rule is what we say addressed; in order that both scholars may display much solicitude about their teachers, and the teachers may have the same loving affection as Paul about those placed under them; not those present only, but also those who are far off.
For also Paul, dwelling in the whole world just as in one house, thus continually took thought for the salvation of all; and having dismissed every thing of his own; bonds and troubles and stripes and straits, watched over and inquired into each day, in what state the affairs of the disciples were; and often for this very purpose alone sent, now Timothy, and now Tychicus; and about him he says, “That he may know your circumstances, and encourage your hearts:” and about Timothy; “I have sent him, being no longer able to contain myself; lest in some way the tempter have tempted you.” And Titus again elsewhere, and another to another place.
For since he himself, by the compulsion of his bonds being often detained in one place, was unable to meet those who were his vitals, he met them through the disciples.
Source: Homily Concerning "Lowliness of Mind" (New Advent)